The 12 Keys
Western music is built on 12 notes, each a semitone apart. Every scale, chord and arpeggio in Piano Scales Lab can be played starting from any of these 12 root notes.
Major Scale
The major scale is the foundation of Western tonal music. It has a bright, settled sound and is the starting point for most music theory.
Interval pattern (semitones):
| Key | Notes |
|---|---|
| C Major | C D E F G A B |
| G Major | G A B C D E F# |
| D Major | D E F# G A B C# |
| F Major | F G A Bb C D E |
Natural Minor Scale
The natural minor scale has a darker, more melancholic sound than major. It uses the same notes as its relative major but starts on the 6th degree.
Interval pattern:
Harmonic Minor Scale
The harmonic minor raises the 7th degree of the natural minor by a semitone. This creates a stronger pull back to the root and gives the scale its distinctive exotic sound.
Interval pattern:
Melodic Minor Scale
The melodic minor raises both the 6th and 7th degrees when ascending, then reverts to natural minor when descending. This smooths out the augmented second of the harmonic minor.
Ascending intervals:
Descending: same as natural minor, played in reverse. Switch between ASC and DESC on the Scales page to see both.
Chromatic Scale
The chromatic scale includes all 12 semitones within an octave. Every note is equally spaced — there is no tonal centre beyond the starting note.
Interval pattern: all semitones (1 1 1 1 1 1 1 1 1 1 1 1)
Fingering rule: finger 3 on every black key, finger 1 on most white keys, finger 2 used at E-F and B-C (where two white keys sit adjacent with no black key between them).
Chromatic scales do not have relative or parallel counterparts — those buttons are disabled when Chromatic is selected.
Arpeggios
An arpeggio is a chord played one note at a time. The app covers major and minor arpeggios over two octaves.
Major arpeggio intervals:
Minor arpeggio intervals:
Relative and Parallel Keys
Relative keys
A major key and its relative minor share the same notes and key signature. C Major and A Natural Minor are relatives — both use the white keys only. The relative minor starts on the 6th degree of the major scale.
Parallel keys
Parallel keys share the same root note but have different scales. C Major and C Minor are parallel — both start on C but use different notes.
The Relative button in the app cycles between a major key and its relative minor — useful for practising both in the same session.
Chords and Progressions
A chord is three or more notes played together, usually built by stacking thirds. The chords built on each degree of a major scale follow a fixed pattern:
| Degree | Roman numeral | Quality |
|---|---|---|
| 1st | I | Major |
| 2nd | ii | Minor |
| 3rd | iii | Minor |
| 4th | IV | Major |
| 5th | V | Major |
| 6th | vi | Minor |
| 7th | vii° | Diminished |
Fingering Numbers
| Number | Finger |
|---|---|
| 1 | Thumb |
| 2 | Index finger |
| 3 | Middle finger |
| 4 | Ring finger |
| 5 | Little finger (pinky) |
Fingering shown in the app follows standard classical conventions. You can customise any scale in the Fingering Editor.